Prebiotics as functional foods: A review

Prebiotics are short chain carbohydrates that are non-digestible by digestive enzymes in humans and selectively enhance the activity of some groups of beneficial bacteria. In the intestine, prebiotics are fermented by beneficial bacteria to produce short chain fatty acids. Prebiotics also render many other health benefits in the large intestine such as reduction of cancer risk and increase calcium and magnesium absorption. Prebiotics are found in several vegetables and fruits and are considered functional food components which present significant technological advantages. Their addition improves sensory characteristics such as taste and texture, and enhances the stability of foams, emulsions and mouthfeel in a large range of food applications like dairy products and bread. This contribution reviews bioactives from food sources with prebiotic properties. Additionally, food application of bioactive prebiotics, stimulation of the viability of probiotics, health benefits, epidemiological studies, and safety concerns of prebiotics are also reviewed.     

Viability and Activity of Bifidobacteria During Refrigerated Storage of Yoghurt Containing Mangifera pajang Fibrous Polysaccharides

Abstract: The viability and activity of Bifidobacterium pseudocatenulatum G4, B. longum BB 536 and yoghurt cultures (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) were studied in yoghurt containing 0.75%Mangefira pajang fibrous polysaccharides (MPFP) and inulin. Growth of probiotic organisms, their proteolytic activities, the production of short chain fatty acids (lactic, acetic and propionic) and the pH of the yoghurt samples were determined during refrigerated storage at 4 °C for 28 d. B. pseudocatenulatum G4 and B. longum BB 536 showed better growth and activity in the presence of MPFP and inulin, which significantly increased the production of short chain fatty acids as well as the proteolytic activity of these organisms. Practical Application: This is the first study reported on produce synbiotic yoghurt as a functional food for specified health uses contains bifidobacteria and M. pajang fibrous polysaccharides. M. pajang fibrous polysaccharides can be used as a prebiotic particularly in dairy products to increase the viability and activity of bifidobacteria which can be used as probiotic to exert health benefit to the human by yoghurt that is considered common use in society; thus, the benefits of synbiotic yoghurt are readily accessible to the member of society.     

Influence of food structure on dairy protein,lipid and calcium bioavailability: A narrative review of evidence

Beyond nutrient composition matrix plays an important role on food health potential, notably acting on the kinetics of nutrient release, and finally on their bioavailability. This is particularly true for dairy products that present both solid (cheeses), semi-solid (yogurts) and liquid (milks) matrices. The main objective of this narrative review has been to synthesize available data in relation with the impact of physical structure of main dairy matrices on nutrient bio-accessibility, bioavailability and metabolic effects, in vitro, in animals and in humans. Focus has been made on dairy nutrients the most studied, i.e., proteins, lipids and calcium. Data collected show different kinetics of bioavailability of amino acids, fatty acids and calcium according to the physicochemical parameters of these matrices, including compactness, hardness, elasticity, protein/lipid ratio, P/Ca ratio, effect of ferments, size of fat globules, and possibly other qualitative parameters yet to be discovered. This could be of great interest for the development of innovative dairy products for older populations, sometimes in protein denutrition or with poor dentition, involving the development of dairy matrices with optimized metabolic effects by playing on gastric retention time and thus on the kinetics of release of the amino acids within bloodstream.     

Influence of feed and water on the stable isotopic composition of dairy milk

Traceability of dairy products is an important issue for the dairy industry. Empirical studies have demonstrated the utility of stable isotope measurements on milk for verification of origin. However, various drivers influence the isotopic composition of a food stuff, such as rainfall levels or food supplements. Relationships between the isotopic composition (δ²H, δ¹⁸O, δ¹³C and δ¹⁵N) of milk fatty acids, the water component of the milk, and feed and farm water from 18 New Zealand dairy farms were studied. Significant relationships between the isotopic composition of milk and both farm water and feed fatty acids were observed. Measurement of both diet and drinking water from each dairy farm enabled the underlying environmental correlations to milk fatty acids to be explored by analysis of their respective δ²H values. Development of this technology may provide a diagnostic tool for determining type and the origin of dietary feed utilised in milk production.     

Exclusive quantification of methyl-branched fatty acids and minor 18:1-isomers in foodstuff by GC/MS in the SIM mode using 10,11-dichloroundecanoic acid and fatty acid ethyl esters as internal standards

Minor fatty acids (iso- and anteiso-fatty acids, vaccenic acid, elaidic acid) in foodstuff (seafood, milk, and dairy products) were analyzed by gas chromatography with electron ionisation mass spectrometry in the selected ion monitoring mode (GC/EI-MS-SIM). For this purpose, lipids were obtained by accelerated solvent extraction (ASE) and the fatty acid constituents were converted into methyl esters. Instead of the determination of the relative contribution of the minor fatty acids to the sum of all fatty acids detected (the so-called 100% method), we exclusively quantified the minor fatty acids, which was possible by using two types of internal standards (IS-1 and IS-2). For recovery checks during the extraction and/or the transesterification step we added the novel 10,11-dichloroundecanoic acid (DC-11:0) as IS-1. DC-11:0, which has never been detected in foodstuff, was synthesized by electrophilic addition of chlorine to 10-undecenoic acid (11:1n-10). The novel IS eluted in the range of 23:0 from the polar GC column used and showed the same properties as fatty acids in foodstuff during sample preparation. Recovery rate of DC-11:0 was generally >96% in the various samples analyzed. Ethyl esters (FAEE) of a12:0, a14:0, a15:0, a16:0, a17:0, and a18:0 (IS-2) were added to both the external standard (a quantitative mixture of methyl esters of methyl-branched fatty acids and 18:1n-9trans) in order to determine their response factors relative to FAEE and to the food samples. With this technique, (only) methyl-branched fatty acids (MBFAs) as well as vaccenic acid (18:1n-7) and elaidic acid (18:1n-9trans) were quantified in a range of dairy products (including twelve cheeses) and seafood. All samples were analyzed in triplicates, and good standard deviations (concentrations 0.002–5 g/100 g; standard deviations 0.00–0.03) were obtained in all cases. MBFAs were detected in all samples analyzed. The highest content of MBFAs (3.0 g/100 g) was determined in red-smear of romadur cheese. In all except two cheeses, i17:0 was the most abundant MBFA. The highest amount of 18:1n-9trans was found in feta (2.84 g/100 g) whereas 0.03 g/100 g in big eye snapper (Pricanthus tayenus) marked the lowest record of this minor fatty acid. Seal oil contained the highest amount of 18:1n-7 with 5.00 g/100 g, whereas emmental cheese was the sample with the lowest content of this monoenoic fatty acid. The combination of suitable IS and a sensitive GC/EI-MS-SIM method proved to be well suited for the quantification of minor fatty acids in foodstuff. When only a set of fatty acids is going to be analyzed, this method is less time consuming compared to “100% methods” and less prone to false results due to the higher selectivity of GC/MS compared to GC in combination with flame ionisation detection (GC/FID).     

Optimization of the GC method for routine analysis of the fatty acid profile in several food samples

The fatty acids profile of food samples was determined by gas chromatography (GC). The fat was extracted from different food samples using Soxhlet technique. Extracted triglycerides were converted to corresponding methyl esters using methanolic solution of potassium hydroxide (trans-esterification). GC method for the analysis of obtained methyl esters was optimized on two different cyanopropyl capillary columns. Good resolution of all fatty acids commonly found in foodstuffs was achieved. After optimization, the method was validated and the results for linearity, precision, limit of quantitation (LOQ), limit of detection (LOD), robustness and stability were presented. The method has been applied to the quantitative determination of the fatty acid content in different food samples: edible oil, dairy products rich with omega-3 fatty acids, different food supplements, baby food, etc.     

FATTY ACID COMPOSITION AND CONJUGATED LINOLEIC ACID CONTENT OF COW AND GOAT CHEESES FROM NORTHWEST ARGENTINA

ABSTRACT

In this study, we evaluated chemical characteristics, fatty acid composition and conjugated linoleic acid (CLA) content of cow and goat cheeses from Northwest Argentina. Similar chemical and fatty acid composition were determined in milk and cheese of both species. Palmitic, oleic and myristic acids were the most abundant fatty acids in dairy products. CLA level averaged 0.85 and 0.96 in milk and 0.76 and 1.04 g/100 g of fatty acids in cheese of cow and goat, respectively. Cis‐9,trans‐11 was the major isomer present in both species. Significant differences in CLA desaturase activity were observed, showing a value of 0.068 and 0.064 in milk, and 0.077 and 0.071 in cheese of cow and goats, respectively. Good nutritional properties were determined for cheeses of both species, which are fed on natural pasture during spring and summer seasons. Goat's cheese represents a higher source of CLA for human consumers than cow's cheese, offering from 156.6 to 222.6 mg/ 100 g of sample.

PRACTICAL APPLICATIONS

The present work shows the fatty acid composition and chemical characteristics of two fresh cheeses manufactured with cow and goat milk. Animals were fed on natural pasture during summer and spring seasons. It is known that pasture increases conjugated linoleic acid (CLA) concentration in milk fat, and the content in cheese is directly related to it. The CLA content of dairy products for the human consumers was analyzed, showing goat cheese with high polyunsaturated fatty acid content, including CLA. Cow and goat fresh cheese offer CLA as many ripening products of different countries, as cheddar or hard cheeses. Lipid composition of food is related to many illnesses, but some compounds are beneficial to human health. The main sources of CLA are milk and cheeses, and in Northwest of Argentina, no data are reported about it, where artisanal cheeses are consumed by the population. Therefore, the atherogenicity index was determined as well.     

Production of Bioingredients from Kluyveromyces marxianus Grown on Whey: An Alternative

Whey waste is a major problem for the dairy industry. Finding alternative means to reduce its pollution potential and produce high value-added bioingredients has been attempted by many researchers. Kluyveromyces marxianus var. marxianus is a dairy yeast that produces β-galactosidase, allowing for whey fermentation. Also, K. marxianus has been proposed as a source of: (1) oligonucleotides, used as flavor enhancers in food products; (2) oligosaccharides, used as prebiotics to stimulate the growth of Bifidobacterium sp. in the animal and human intestines; and (3) oligopeptides, immunostimulators added to dairy products that are released in the wort after whey protein proteolysis. Fed-batch fermentation can be used as an alternative process to avoid increases in lactose concentration and prevent the catabolite repression of the respiratory enzyme synthesis during aerobic fermentation, thus allowing for high biomass yields. The relevance of these factors on yeast fermentation of whey is summarized in this critical review.     

Direct quantification of fatty acids in dairy powders with special emphasis on trans fatty acid content

In this study a validated procedure for accurate determination of fatty acids in dairy products, with special emphasis on total trans fatty acids (TFA) content is presented. Dairy fat naturally contains 4–6% of trans fatty acids, mainly trans-octadecenoic acids (i.e. vaccenic acid), and 0.3–1.5% of conjugated linoleic acids (CLA). The proposed procedure does not require lipid extraction, and transesterification of lipids could be carried out directly on dairy products. Optimal analytical conditions have been developed to allow accurate determination of TFA content without prior fractionation of cis/trans FAME isomers by thin-layer chromatography. The methodology requires the use of a highly polar open tubular capillary column having at least 100 m length. CLA and other fatty acids from C4:0 (butyric) acid to long-chain polyunsaturated fatty acids (LC-PUFAs) could also be analyzed. Therefore, the methodology presented is versatile and could be used for both targeted analysis (e.g. determination of TFA in dairy products) and determination of the broad fatty acid profile in dairy products.     

Overview of Food Safety Hazards in the European Dairy Supply Chain

Monitoring of dairy products should preferably focus on the most relevant food safety hazards in the dairy supply chain. For this purpose, the possible presence of microbiological, chemical, and physical hazards as well as trends in the dairy supply chain that may affect their presence were assessed. A literature review was combined with available data from EFSA, RASFF, and the Dutch monitoring program on chemical hazards as well as expert information. This study revealed that microbiological hazards are encountered more frequently in dairy products than chemical and physical hazards. Listeria monocytogenes, Staphylococcus aureus, Salmonella, and human pathogenic Escherichia coli were identified as the most important microbiological hazards in dairy products. Soft and semisoft cheeses are most frequently associated with L. monocytogenes and S. aureus enterotoxins, whereas raw milk is most frequently associated with human pathogenic E. coli and Campylobacter spp., Cronobacter spp., and Salmonella spp. are the microbiological hazards of most concern in powdered infant formula. Based on literature, monitoring, and RASFF data, the most relevant chemical hazards in dairy products are aflatoxin M₁, dioxins, and dioxin‐like compounds and residues of veterinary drugs. Chemical hazards primarily occur at the dairy farm and may accumulate during further processing. The most relevant physical hazards are metal, glass, and plastic particles introduced during processing. Analysis of trends in the near future revealed that increased milk production is seen as most relevant in relation to food safety. Other trends affecting food safety are climate change and changes at the farm level, which aim to improve animal welfare and environmental sustainability.     

Flavour development in dairy cream using fish digestive lipases from Chinook salmon (Oncorhynchustshawytscha) and New Zealand hoki (Macruronusnovaezealandiae)

Digestive lipases from Chinook salmon and New Zealand hoki were evaluated as flavour modifying agents in dairy products. Cream was incubated either with fish lipase or commercially available lipases used in dairy flavour development – calf pregastric esterase (Renco™ PGE) and microbial lipase (Palatase® 20,000 L). The fish enzymes were more similar to calf PGE in terms of the total amount and types of fatty acids released over the course of the reaction. Like the pregastric esterase, the fish enzymes released mainly short chain fatty acids. The highest specificity was towards the key dairy product flavour and odour compounds, butanoic and hexanoic acids. The odour intensity of hexanoic acid produced by the salmon lipase, as measured by SPME–GC–MS, was similar to that produced by both Palatase® and PGE. Free fatty acid composition, together with sensory characteristics of lipase-treated creams, demonstrated the potential for flavour enhancement in dairy products using fish lipases.     

Isolation and Screening of Lipase-Producing Fungi with Hydrolytic Activity

Lipases are enzymes that can be secreted by several microorganisms, making interesting the biodiversity exploration for searching new microorganisms able to produce these enzymes. Many agro-industrial residues can be used as potential substrates for production of enzymes. The main objective of this work was the isolation and screening of microorganisms with potential to produce lipases. Among 24 fungi, five were selected as good lipase producers using tributyrin on agar plates and solid state fermentation of soybean bran. Two of them were isolated from soil samples, another two from soybean bran, and one from dairy products. These fungi were identified by microcultivation technique as from Penicillium and Aspergillus genera. Through random amplified polymorphic DNA technique, the most promising strains could be genetically discriminated, selecting two fungi as good lipase producers but genetically different. One isolated from soybean bran could hydrolyze efficiently triglycerides with fatty acids with different chain length. Another isolated from dairy products was only effective to hydrolyze triglycerides with long-chain fatty acids. Two distinct groups could be verified by means of this technique, comprising the most productive strains and the lowest or nonproductive ones in terms of hydrolytic activity.     

Milk fatty acids and potential health benefits: An updated vision

BackgroundMilk fat intake is often associated with a high risk of suffering from cardiovascular disease (CVD) due to its high saturated fat content. However, not all saturated fatty acids (SFA) are equal and they present structural differences that promote distinct effects on the biological processes. In addition, there is a growing scientific consensus pointing to dairy fat as a natural source of bioactive components.Scope and approachThe present review provides the most recent knowledge on the bioactive properties of fatty acids detected in dairy products and their potential effects on consumer health. The metabolic processes that involve these fatty acids and serious chronic diseases such as CVD, obesity, diabetes or cancer are explained and discussed throughout the text based on in vitro, animal and human studies. Moreover, information gaps are highlighted to inspire further research in the field.Key findings and conclusionsRecent investigations support that milk SFA should no longer be considered as a single group in terms of metabolism or negative effects in case of excess. Even they suggest that individual SFA possess specific properties associated with important physiological functions. Whole dairy products would also promote human health due to the presence of certain bioactive fatty acids. Among them, it is worth mentioning the maintenance of gut microbiota and weight control from short and medium-chain SFA, the essential role of branched-chain SFA in gut health at birth and the prevention of chronic inflammatory diseases by vaccenic and rumenic acids.     

Food chain approach to lowering the saturated fat of milk and dairy products

Lactating cow diets were supplemented with high‐oleic acid sunflower oil over two production periods spanning two years, to modify the milk fat, partially replacing saturated fatty acids with cis‐monounsaturated fatty acids. The resulting milk was used for ultrahigh‐temperature milk, butter and Cheddar cheese production, and fatty acid profiles were compared with those of conventionally produced products. Fat from products made with modified milk had lower saturated fatty acids and higher cis‐ and trans‐monounsaturated fatty acid concentrations than that of conventional products. This was consistent over both production periods, demonstrating that this food chain approach could be adopted on a wider scale.     

我国全麦食品品质改良研究进展

全麦食品含有丰富的不饱和脂肪酸、膳食纤维、高活性酶以及酚类和多糖类活性物质,使其食用价值和营养价值远高于常规面制品。因其特殊的化学组成,若完全依照常规面制品的加工方式进行加工,制得的全麦食品存在食用品质不佳和耐储藏性较差等问题。因此,在尽可能保持全麦食品原有营养成分的前提下,如何提高其食用品质和耐储藏性俨然成为我国全麦食品产业所面临的首要问题。综述近年来我国全麦食品的品质改良方法及研究进展,为我国全麦食品的进一步研究开发提供参考依据。     

Influence of starter cultures on the free fatty acids during ripening in Tea sausages

The influence of starter cultures on the free fatty acids content during ripening of Tea sausages, typical dry sausages produced in the south of Croatia, was studied. Three batches of Tea sausages were produced using different starter mixtures (Staphylococcus xylosus S81 and Lactobacillus sakei G20; Staphylococcus xylosus S142 and Lactobacillus sakei G20; Staphylococcus xylosus S206 and Lactobacillus sakei G20), while the control batch was produced without a starter. The amounts of free fatty acids present in the samples at the end of the ripening period were not significantly different, suggesting that the lipolytic enzymes naturally occurring in meat could play a predominant role in the free fatty acids release. Oleic and linoleic acids were present in the highest concentrations, while only small quantities of short-chain fatty acids were detected, with acetic acid being the most representative one.     

脂肪酸检测在食品工业中的应用研究进展

脂肪酸是油脂的重要组成成分,不同食品脂肪酸组成与含量存在差异性,通过脂肪酸分析可以溯源产地、区分品种、分析品质优劣、开发高质量产品。文章论述了脂肪酸检测在肉品、乳与乳制品、植物油、药食同源食材中的应用。     

Biochemical characteristics,virulence traits and antifungal resistance of two major yeast species isolated from kefir: Kluyveromyces marxianus and Saccharomyces unisporus

Kefir yeasts were investigated for their possible virulence using an in vitro system. Unweighted pair group method with arithmetic mean (UPGMA) cluster analysis of 46 biochemical traits showed that all kefir isolates formed clusters distinct from Candida albicans. No isolate showed N‐acetylglucosaminidase activity, which is involved in resistance against host immune systems. All Kluyveromyces marxianus isolates formed pseudohyphae and grew at 42 °C, whereas Saccharomyces unisporus isolates did not. None of the kefir yeasts had proteolytic or haemolytic activities. All K. marxianus isolates were susceptible to fluconazole, whereas S. unisporus isolates were classified as resistant.     

Ice Cream as a Vehicle for Incorporating Health‐Promoting Ingredients: Conceptualization and Overview of Quality and Storage Stability

Ice cream is a product with peculiar textural and organoleptic features and is highly appreciated by a very broad spectrum of consumers. Ice cream's structure and colloidal design, together with its low‐temperature storage, renders it a very promising carrier for the stabilization and in vivo delivery of bioactive compounds and beneficial microorganisms. To date, many applications related to the design and development of functional ice cream have been documented, including products containing probiotics, prebiotics, synbiotics, dietary fibers, natural antioxidants such as polyphenols, essential and polyunsaturated fatty acids, and low glycemic index blends and blends fortified with mineral or trace elements. In this review, promising strategies for the incorporation of innovative functional additives to ice cream through the use of techniques such as microencapsulation, nanoemulsions, and oleogels are discussed, and current insights into the implications of matrix, processing, and digestion on bioactive compounds in frozen dairy desserts are comprehensively reviewed, thereby providing a holistic overview of the current and emerging trends in this functional food sector.